[lammps-users] Simulating a LJ solute in Water

Hi,
I was trying to setup a simulation with a Lennard Jones solute (the solute interacts according to a LJ potential with the oxygen of water) and SPCE water. The input file I have access to just has the positions of the water molecules. To simulate the solute, I created a particle (heavy particle) and introduced LJ interactions between this and the oxygen of the water molecules. I chose random initial conditions for this solute particle and chose a small sigma for this LJ interaction so as to avoid clashes (in case the solute overlaps with a water molecule). To "grow" the solute, I attempted to change the value of sigma in between runs
run 1000 start 0 stop 3000
pair_coeff 1 3 0.1 0.3
run 1000 start 0 stop 3000
pair_coeff 1 3 0.1 0.4
run 1000 start 0 stop 3000

Do you think this will work ? I am new to LAMMPS and am still trying to figure things out. Is there an easier way to accomplish this ?

Thanks

Suriyanarayanan Vaikuntanathan

You don't need the start/stop options. You can certainly change
sigma, or whatever else you want, in between runs.

Steve